It’s literally what’s happening.
Texas used the same concept to empower private people to sue abortion providers and receivers under civil law since they couldn’t do it criminally.
The country as a whole has done it for a long time with cellphone data, the five eyes alliance, etc.
They have access to information they’re barred from getting directly themselves, and they get it from private companies. Spying by proxy.
Very unlikely. There’s a statement at the bottom that explains what the fee is. There’s a QR code at the top for more information, which OP cut off.
I doubt they went through the effort of updating their POS system, providing links to info on the receipt, and chose not to post a sign or put a note on the menu. Everywhere I have been with a service fee like this posts it, which would negate any legal issue.
Caveat emptor.